1. Field of the Invention
This invention relates generally to an apparatus and method for shoulder arthroplasty and, more particularly, to a glenoid component and other associated surgical components and instruments for use in shoulder arthroplasty.
2. Discussion of the Related Art
A natural shoulder joint may undergo degenerative changes due to a variety of etiologies. When these degenerative changes become so far advanced and irreversible, it may ultimately become necessary to replace a natural shoulder joint with a prosthetic shoulder joint. When implantation of such a shoulder joint prosthesis becomes necessary, the natural head portion of the humerus is resected and a cavity is created in the intramedullary canal of the host humerus for accepting a humeral component. The humeral component includes a head portion used to replace the natural head of the humerus. Once the humeral component has been implanted, the glenoid cavity positioned at the scapula head may also be resurfaced and shaped to accept a glenoid component. The glenoid component generally includes an articulating surface which is engaged by the head portion of the humeral component.
It is generally known in the art to provide a shoulder joint prosthesis having a glenoid component, as discussed above. However, the current prior art glenoid components along with the associated surgical components and instruments utilized during shoulder arthroplasty suffer from many disadvantages.
For example, since the glenoid component is subject to various types of loading by the head portion of the humeral component, the glenoid component must offer a stable and secure articulating surface. To achieve this, some glenoid components provide pegs which are inserted and cemented into holes bored into the glenoid cavity. However, such existing pegged glenoid components also exhibit several disadvantages. For example, some of the pegged glenoid components utilize up to five pegs to stabilize and secure the glenoid component to the scapula. Such glenoid components increase the amount of bone tissue removed, while also increasing the labor and complexity of the shoulder arthroplasty. Other pegged glenoid components may offer one or two larger diameter pegs which reduces the complexity of the shoulder arthroplasty. However, the larger diameter pegs also requires excess bone tissue to be removed which may not be practical in some patients. Furthermore, the use of one or two pegs may potentially reduce overall stability of the glenoid component, similar to a keeled glenoid.
Additionally, most prior art glenoid components only rely on the keel or pegs to secure the glenoid component to the scapula, via a cement mantle. The keel or pegs may also include grooves or holes which act as an anchor once the keel or pegs are cemented within the glenoid cavity. The medial surface of most glenoid components are thus generally overlooked to enhance cement fixation and are therefore generally smooth. Although, some glenoid components may include a few longitudinal grooves and others may include both grooves and depressions on the medial surface. However, such surface enhancements only utilize or texture a portion of the medial surface, thereby not advantageously using the entire medial surface. Moreover, such glenoid components do not provide for a uniform cement mantle at the medial surface.
What is needed then is a glenoid component and associated surgical components for use in shoulder arthroplasty which does not suffer from the above-mentioned disadvantages. This in turn, will provide a glenoid component which is stable and secure, reduces the overall amount of bone tissue required to be removed, reduces the overall surgical time and complexity, increases overall medial surface area, enhances and increases attachment strength without increasing overall peg diameter, provides a fully enhanced or textured medial surface for enhanced cement fixation and increased overall stability, provides for a uniform cement mantle, and provides increased tensile and shear strength. It is, therefore, an object of the present invention to provide such a glenoid component and associated surgical components for use in shoulder arthroplasty.
In accordance with the teachings of the present invention, an apparatus and method for shoulder arthroplasty is disclosed. The apparatus and method employs a glenoid component and other associated surgical components for use in the shoulder arthroplasty. In this regard, the glenoid component is adapted to be implanted into a scapula at the glenoid fossa or cavity and engaged by a head portion of a humeral component.
In one preferred embodiment, a glenoid component is used for shoulder arthroplasty such that the glenoid component is adapted to be implanted into a scapula and engaged by a head of a humeral component. The glenoid component includes a body having a first articulating surface and a second medial surface which is opposite to the first articulating surface. The first articulating surface is adapted to be engaged by the head of the humeral component and the second textured medial surface is adapted to be secured to the scapula. A plurality of curved pegs each have a first end adapted to engage a cavity formed in the scapula and a second end extending from the medial surface. Each of the curved pegs is partially defined by four depending sidewalls having a square cross-section.
Use of the present invention provides an apparatus and method for shoulder arthroplasty, and specifically, a glenoid component and associated surgical components for use in shoulder arthroplasty. As a result, the aforementioned disadvantages associated with the currently available glenoid components and associated surgical components for shoulder arthroplasty have been substantially reduced or eliminated.
The present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.